1. Field of the Invention
The invention generally relates to a locking method and mechanism for a retractable device for connecting a member, and adjusting the relative linear position of the member.
2. Related Art
Many kinds of retractable devices are used in common apparatus, including machines, home appliances and electronic products, for user to adjust some components to their suitable positions for use.
For example, many computer monitors have been replaced from prior bulky CRT (cathode ray tube) to current flat panel LCD (liquid crystal display). CRT is heavy and usually mounted on a pivotal base for angular adjustment only. LCD is compact and light so the base of a LCD panel is not only provided with angular adjustment, but also provided with height adjustment.
A conventional LCD supporting member mainly includes a base and a supporting rod. The rod supports the LCD panel in a retractable manner. A spring is included in the rod for extending the length of the rod during adjustment. When being packed, the rod is retracted into the base to save space for easier delivery. In order to prevent the rod suddenly extrude from the base, a latch is usually provided at the base for locking the rod in position when being retracted. However, the latch is easy to be released unintentionally during delivery by some external force. The rod may not fully extend because of being packed, but it will suddenly burst out and hurt people when being unpacked. Another accident is that, during use, the latch being unintentionally moved by user and suddenly extends to hurt the user.
There is also a kind of safety latch or switch for locking the latch. The user has to release the safety latch before operate the main latch for releasing the movable mechanism. However, the double latch system is not convenient for use.
As described above, a conventional retractable supporting member for LCD panel may has only one latch for fixing the position of adjusted element. The one latch device cannot prevent unintentional release of the latch and may cause accident. Though conventional retractable supporting member may have additional safety latch for locking the main latch, the operation is not easy for users.